One or more kinds of color vision tests were given to patients and subjects registered in this and related projects. In addition to the color tests, dark adaptation studies with measurements of rod and cone thresholds were made on many patients, particularly those who were beginning or maintaining medications thought to affect visual function. Tests were conducted on 319 patients during the year, including some normal controls. It was found that the Hardy-Rand-Rittler Pseudoisochromatic Plates and the Farnsworth Panel D-15 are not sufficiently sensitive to reveal subtle defects in color vision, so most of the color tests were done with the Lanthony Desaturated Panel D-15, the Farnsworth-Munsell 100-Hue test, and the Gunkel Chromagraph. Three kinds of tests were used in an effort to determine their relative consistency, suitability, sensitivity, and validity for use with patients having different types and degrees of illness.